Looper mechanism for sewing machines



1935- F. A. KUCERA LOOPER MECHANISM FOR SEWING MACHINES Filed Dec. 26, 1933 Patented Dec. 3, 1935 UNITED STATES LOOPER MECHANISM FOR SEWING MACHINES Frank A. Kucera, Chicago, Ill., assignor to Union Special Machine Company. Chicago, 111., a corporation of Illinois Application December 26; 1933, Serial No. 704,015

7 Claims.

The invention relates to new and useful improvements in a looper mechanism for sewing machines, and more particularly to a 'ineans for supporting the looper whereby it may be moved to a position where it is readily accessible for threading.

An object of the invention is to provide a looper supporting means wherein the looper is mounted on an operating shaft therefor so that said looper may be released and swung about an axis lying in a plane at right angles to the axis of the operating shaft for positioning the looper so that it is readily accessible for threading.

In the drawing, which shows by way of illustration one embodiment of the invention:

Figure 1 is a longitudinal sectional view through the end of a work supporting arm and showing the improved looper operating mechanism which is mounted therein.

Figure 2 is a plan view of the operating shaft for the looper and the means for supporting the looper, and showing in broken lines the looper released and returned to position for threading.

Figure 3 is an end view of the looper holder and the supporting means whereby the holder is mounted on the operating shaft.

Figure 4 is a sectional view on the line 44 of Figure 1, also showing in broken lines the position to which the looper is turned for threading.

Figure 5 is a plan view of the latching means, showing the latch as about to enter the holding member therefor.

Figure 6 is a view showing the latching member as moved into the holder.

Figure '7 is a plan view of the latching means and the support beneath the holding means, and

showing the lugs for preventing lateral movement of the looper holder endwise of its pivotal support.

Figure 8 is a section on the line 8-8 of Figure 4.

The invention is directed to a looper mechanism for sewing machines, and more particularly to a looper mechanism which is used in connection with a cylindrical work supporting arm. In the patent granted Frederick F. Zeier and Landauer P. Edmiston, June 6, 1933, No. 1,912,959, there is shown a looper mechanism of the above type wherein the looper holder is so connected to the operating shaft therefor that it may be released and turned on the shaft to a position which renders the looper more readily accessible for threading. The looper holder is swung to threading position by a movement of the holder about the axis of the operating shaft.

The present invention is an improvement on the structure shown in the Zeier and Edmiston patent. The looper holder is fixedly attached to the operating shaft therefor in such a way that it may be released and swung about an axis at right angles to the axis of oscillation of the operating shaft. This gives a greater. range of 5 movement to the looper and permits the placing of the same relative to the throat plate in a more accessible position for threading.

It is thought that the invention will be better understood by a detail description of the illus- 10 trated embodiment thereof.

In the drawing, the cylindrical work support is indicated at I. Carried. by said cylindrical work support is a throat plate 2. The fabric is held against the throat plate by a pre-sser foot 3. As shown, the machine is provided with three needles indicated at 6, l, and 8. Cooperating with the needle 6 is a looper 9; cooperating with the needle i is a looper it; and cooperating with the needle 8 is a looper ll. While the invention is shown as applied to a three-needle machine, it will be understood that it may be used in connection with two needles or one needle; and in the description of the invention a single looper will be referred to, but purely for the purpose of simplifying the description rather than limiting the invention. The loopers cooperate independently with the needles in the forming of lines of stitches.

Extending lengthwise of the cylindrical work supporting arm is an operating shaft 12. This shaft l2 extends into a sleeve I3 and is fixed to said sleeve. The sleeve in turn is journaled in a'bushing I4 mounted in an end bracket l5 of the work supporting arm. Mounted on the end of the sleeve adjacent the looper is a looper support I6. Said sleeve has a reduced portion forming a shoulder l1 and the support l6 fits onto this reduced portion engaging against the shoulder l1. Extending all the way through the support is an opening in which is located a lock- 40 ing pin I8. This opening is so disposed that the center thereof is substantially tangent to the outer diameter of the reduced portion of the sleeve l3. The sleeve is cut away so that the pin l8 extends through the opening in the wall of the sleeve. The pin has a cut-away portion lBa therein, and this cut-away portion is placed in registerwith the opening through the sleeve when the sleeve is inserted onto the shaft. The pin is then forced endwise by means of the nut I812 which causes the curved wall of the recess I8a to grip the side of the shaft and firmly secure the sleeve to the shaft so that the sleeve will oscillate and move endwise with the shaft. This means for securing the sleeve carrying looper holder to the shaft permits of the adjustment of the sleeve endwise of the shaft and also angularly of the shaft. Through these two adjustments the proper positioning of the loopers relative to the needles may be obtained.

The looper support is in the form of a laterally extending head and at one side thereof are spaced lugs l9 and 253. The looper holder 2| is provided with a projecting arm 23 which lies between the lugs l9 and Z8, and the pivot pin 24 passes through the lugs I9 and Eli, and the arm '23, and thus the looper holder is pivoted to the looper support it. The loopers 9, l0, and H are mounted on this looper holder and are secured thereto by set screws 22. The axis of this pivot pin 24 lines in one plane cutting the axial line of the shaft I? at right angles. The axis of the pivot pin is also disposed laterally at one side of the axis of the shaft and lies at an angle to the axis of the shaft l2.

The laterally extending head of the looper support at the side opposite the lugs I9 and 2B is provided with laterally spaced arms 25 and 26, see Figure '7. The looper holder has a laterally projecting portion 2'11 which carriesa lug 28 at its outer end, and this lug 23 is adapted to fit between the arms 25 and 26 when the looper holder is swung to the position shown in full lines in Figures 2 and 4 and when the looper is thus positioned for normal operation. These arms, together with the pivot pin, will secure the holder and the looper support so that they are prevented from any lateral movement on the support when said holder is secured in its normal operated position.

The holder is secured to the looper support by a latch mechanism which includes a retaining plate 23 and a latch pin The retaining plate 29 is secured to the iooper support by suitable screws 3?, 3i. Said retaining plate projects outwardly so as to overhang the outer face of thelooper support. Said plate at its outer end is curved substantially about the center of the pivot pin. There is an opening 32 through this plate and a slot 33 leading thereto which provides holding shoulders 34, 3d for the reason that the slot is of less width than the diameter of the opening 32. The extreme outer end of the plate gradually decreases in thickness to form an entering wedge. The latch pin 38 extends through an opening 35 in the looper holder, which opening extends in a direction at right angles to the axis of the pivot pin 24. Said opening is enlarged adjacent the pivot pin and receives a compression spring 33. At the inner end of the latch pin 35 there is a screw 31 having an enlarged head 7 pin in a direction toward the pivot pin 24. The

latch pin 33 is of such a diameter that it may freely pass through the slot 33. At the upper end of the latch pin there is a head 38 which is shaped to conform to the opening 32 so as to freely fit in the opening. When the latch pin is moved from the position shown in Figure 5 to the position shown in the other figures of the drawing, the pin will enter the slot, and the wedge-shaped end of the plate 29 will pass between the head 38 and the holder 21 and force the latch pin outward against the tension of compression spring 36. As soon as the head is brought into register with the opening 32, it will move down into the opening and then said head contacting with the shoulders 34, 34 will prevent any swinging of the holder onto its pivot.

The underside of the head 38 is inclined so as toaid in the wedge shaped plate passing beneath the same. This inclination is a tangent to a curved line formed about the axis of the pivot pin as a center. The holder 2'] directly beneath the head of the pin is likewise inclined or curved about the axis of the pivot as a center.

From the above it will be apparent that pressure on the head of the screw 3! will cause the pivot pin to move endwise and thus release the head 33 from the opening in the retaining plate 29. After this head is moved out of the opening, then the holder can be swung about the axis of the pivot pin so as to position the looper, as indicated in the broken lines in Figures 2 and 4. Inasmuch as the axis of the pivot pin is to one side of the axis of the center of the shaft [2, the looper will be moved well out from underneath the throat plate and thus rendered more accessible for threading than where said looper is shifted about the axis of the shaft as in the Zeier and Edmiston patent. After the looper has been threaded, the operator may turn the holder about its pivot pin so as to return the looper to its normal operating position. When the holder is returned to this operating position, the retaining plate will automatically enter beneath the head 38 and the head will slide over the plate until it can drop into the opening 32.

From the above it will be apparent that a very simple mounting for the looper holder has been provided, wherein said looper holder is positived in its set position for normal operation, by simply pressing on a pin it can be reso that it can be turned to position the loopers where they will be very readily ole for threading. After the loopers have i threaded, then the holder can be returned its nor -al set position and it will automaticaliy b atched and secured in said set position.

It is obvious that minor changes in the details of construction may be made without departing vLldb Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

l. A looper mechanism for sewing machines comprising an oscillating operating shaft, a loopor support fixed to said shaft, a looper holder, a

looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an axis which lies at an angle to theaxis of oscillation of said shaft, and latching means for securing said looper holder to said looper support for retaining the looper in operative position, said latch permitting said looper holder to be released from the looper support and the looper holder swung for positioning the looper for threading.

2. A looper mechanism for sewing machines comprising an oscillating operating shaft, a looper support fixed to said shaft, a looper holder, a looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an axis which. lies at right angles to the axis of oscillation of said shaft, a latch means for securing the looper holder to said looper support for retaining the looper in operative position, said latch means including a retaining plate and a latch pin having a positive interlocking engagement for preventing the holder from turning on its pivotal support.

3. A looper mechanism for sewing machines comprising an oscillating operating shaft, a looper support fixed to said shaft, a looper holder, a looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an axis which lies at right angles to the axis of oscillation of said shaft, a latch means for securing the looper holder to said looper support for retaining the looper in operative position, said latch means including a retaining plate carried by said looper support and a latch pin carried by said holder, said latch pin having a head adapted to engage an opening in said retaining plate for positively securing said looper holder from turning movement on its pivotal support.

4. A looper mechanism for sewing machines comprising an oscillating operating shaft, a looper support fixed to said shaft, a looper holder, a looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an aXis which lies at right angles to the axis of oscillation of said shaft, a latch means for securing the looper holder to said looper support for retaining the looper in operative position, said latch means including a retaining plate secured to said looper support, said retaining plate having an opening therein and a slot leading from said opening of less width than the diameter of the opening, a latch pin carried by the looper holder, said latch pin being dimensioned so as to pass freely through said slot, a head carried by the latch pin of larger dimensions than the slot and adapted to seat in said opening when the looper holder is in its normal operative position.

5. A looper mechanism for sewing machines comprising an oscillating operating shaft, a looper support fixed to said shaft, a looper holder, a looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an axis which lies at right angles to the axis of oscillation of said shaft, a latch means for securing the looper holder to said looper support for retaining the looper in operative position, said latch means including a retaining plate secured to said looper support, said retaining plate having an opening therein and a slot leading from said opening of less width than the diameter of the opening, a latch pin carried by the looper holder, said latch pin being dimensioned so as to pass freely through said slot, a head carried by the latch pin of larger dimensions than the slot and adapted to seat in said opening when the looper holder is in its normal operative position,

and spring means for moving said latch pin so as to seat said head in said opening.

6. A looper mechanism for sewing machines comprising an oscillating operating shaft, a loopor support fixed to said shaft, a looper holder, a looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an axis which lies at right angles to the axis of oscillation of said shaft, a latch means for securing the looper holder to said looper support for retaining the looper in operative position, said latch means including a retaining plate secured to said looper support, said retaining plate having an opening therein and a slot leading from said opening of less Width than the diameter of the opening, a latch pin carried by the looper holder, said latch pin being dimensioned so as to pass freely through said slot, a head carried by the latch pin of larger dimensions than the slot and adapted to seat in said opening when the looper holder is in its normal operative position, said retaining plate being curved about a center substantially coincident with the axis of the pivotal supporting means, the head of said latch pin being inclined so as to be substantially tangential to said curved plate, said retaining plate having its inner and outer faces curved so as to provide an entering wedge whereby said retaining plate will automatically enter beneath the head of the latch pin and cause said latch pin to move over said retaining plate and seat in said opening.

'7. A looper mechanism for sewing machines comprising an oscillating operating shaft, a looper support, a looper holder, a looper carried by said holder, means for pivotally attaching said looper holder to said looper support whereby the looper holder may be swung about an axis which lies at right angles to the axis of oscillation of said shaft, a latching means for securing said looper holder, to said looper support for retaining the looper in operative position, said latching means permitting said looper holder to be released from the support and the looper positioned for threading, a sleeve carried by said shaft on which said looper support is mounted, and a holding pin carried by said looper support and frictionally engaging said shaft to secure said sleeve to said shaft and the looper support in a set position on said shaft, whereby said looper support may be adjusted endwise of the shaft and turned angularly about said shaft.

FRANK A. KUCERA. 

